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Se-Chan Kim Alexander Ghanem Heidi Stapel Klaus Tiemann Pascal Knuefermann Andreas Hoeft Rainer Meyer Christian Grohé Anne A Knowlton Georg Baumgarten 《BMC physiology》2007,7(1):5
Backgound
It has been reported that Toll-like receptor 4 (TLR4) deficiency reduces infarct size after myocardial ischemia/reperfusion (MI/R). However, measurement of MI/R injury was limited and did not include cardiac function. In a chronic closed-chest model we assessed whether cardiac function is preserved in TLR4-deficient mice (C3H/HeJ) following MI/R, and whether myocardial and systemic cytokine expression differed compared to wild type (WT). 相似文献5.
Osmotic Transport across Cell Membranes in Nondilute Solutions: A New Nondilute Solute Transport Equation 总被引:1,自引:0,他引:1
The fundamental physical mechanisms of water and solute transport across cell membranes have long been studied in the field of cell membrane biophysics. Cryobiology is a discipline that requires an understanding of osmotic transport across cell membranes under nondilute solution conditions, yet many of the currently-used transport formalisms make limiting dilute solution assumptions. While dilute solution assumptions are often appropriate under physiological conditions, they are rarely appropriate in cryobiology. The first objective of this article is to review commonly-used transport equations, and the explicit and implicit assumptions made when using the two-parameter and the Kedem-Katchalsky formalisms. The second objective of this article is to describe a set of transport equations that do not make the previous dilute solution or near-equilibrium assumptions. Specifically, a new nondilute solute transport equation is presented. Such nondilute equations are applicable to many fields including cryobiology where dilute solution conditions are not often met. An illustrative example is provided. Utilizing suitable transport equations that fit for two permeability coefficients, fits were as good as with the previous three-parameter model (which includes the reflection coefficient, σ). There is less unexpected concentration dependence with the nondilute transport equations, suggesting that some of the unexpected concentration dependence of permeability is due to the use of inappropriate transport equations. 相似文献
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Effects of carbohydrate on the internal oxygen concentration, oxygen uptake, and nitrogenase activity in detached pea nodules 总被引:2,自引:2,他引:0 下载免费PDF全文
The interaction between carbon substrates and O2 and their effects on nitrogenase activity (C2H2) were examined in detached nodules of pea (Pisum sativum L. cv “Sparkle”). The internal O2 concentration was estimated from the fractional oxygenation of leghemoglobin measured by reflectance spectroscopy. Lowering the endogenous carbohydrate content of nodules by excising the shoots 16 hours before nodule harvest or by incubating detached nodules at 100 kPa O2 for 2 hours resulted in a 2- to 10-fold increase in internal O2, and a decline in nitrogenase activity. Conversely, when detached nodules were supplied with 100 millimolar succinate, the internal O2 was lowered. Nitrogenase activity was stimulated by succinate but only at high external O2. Oxygen uptake increased linearly with external O2 but was affected only slightly by the carbon treatments. The apparent diffusion resistance in the nodule cortex was similar in all of the treatments. Carbon substrates can thus affect nitrogenase activity indirectly by affecting the O2 concentration within detached nodules. 相似文献
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Heidi A. Huczel David H. Clarke 《European journal of applied physiology and occupational physiology》1992,64(5):467-470
Muscular strength and fatigability of strength-trained (ST) and untrained (UT) women were compared during a 6-min bout of maximal rhythmic exercise involving the elbow flexor muscles given at a rate of 30 contractions.min-1. Fifteen ST and 15 UT subjects, aged 18-34 years and pair-matched for body size, were tested for differences in initial strength, final strength, absolute endurance, relative endurance, and rate of fatigue. Results revealed a significant difference in initial strength, final strength, and absolute endurance in favor of ST subjects. No significant difference was found for relative endurance, and rates of fatigue were similar for both groups. It is concluded that muscular strength and endurance are enhanced in women engaged in a training program designed primarily to increase muscular strength and hypertrophy, but fatigability is not affected. 相似文献
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